Stabilizing hydrocarbon products



Patented Aug. 31, 1943 {STABILIZING HYDROCARBON PRODUCTS Robert E. Burkand Everett 0. Hughes, Cleveland Heights, Ohio, assignors to TheStandard Oil Company, Cleveland, Ohio, a corporation of Ohio No Drawing.Application November 29, 1940, Serial No. 367,722-

8 Claims.

It has been known for some time that certain organic compounds mixedwith hydrocarbon products in small amounts result in inhibitindeteriorative changes otherwise prone to occur. For convenience, theterm anti-oxidants has come into use as designating such agents,although chemists are not in agreement as to the accuracy of the term.However, the effects in view are recognized with suficient definiteness.We have now found that certain thio derivatives as more particularlydetailed below, afford improvements in this direction.

To the accompli ent of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described, andparticularly pointed out in the claims, the following descriptionsetting forth in detail certain illustrative embodiments of theinvention, these bein indicative however, of but a few of the variousways in which the principle of the invention may be employed.

Hydrocarbon products prone to deteriorative changes, such as motor fuel,kerosene, lubricating and transformer oils, etc., are. in accordancewith the invention, compounded with a small amount of an agent from thegroup consisting of thio compounds of earbazides and semi-carbazides.Illustrative of such are phenylthiosemicarbazide, o-tolylthiosemicarbazide, diphenylthiocarbazide, diphenylthiosemicarbazide,thiosemicarbazide, etc. Such compounds in general are of the type R H sR \NN-CX/ wherein R is hydrogen or a hydrocarbon radical,

X is NH-N or N, and R aryl groups which may contain substituents, as forinstance amyl, butyl, etc. groups. Particularly desirable are the 4-4substituted thiosemicarbazides. The thio compound can be mixed with thehydrocarbon product in amounts up to several per cent. Products sotreated show excellent results in usage, storage, etc. Thus, withvolatile products such as motor fuel, the thio compound may be used inamounts for instance of 0.0004 to 1 per cent. With oils, such forinstance as oils of 45-200 sec. S. U. at 210 F., 0.1 to 1 per cent issatisfactory.

As an example: Phenylthiosemicarbazide is incorporated in a crackedmotor fuel at the rateof 0.1 g. per gallon. This product on copper dishgum test shows 2.6 mg. The motor fuel without the thio compogdshowed 6.2mg.

' 56 sec. Saybolt at 100 F., sludge 0.3 per cent,

lacquer 12.4 mg., and appearance rating B minus. The oil without suchaddition showed a viscosity increase 258, sludge 9.2 per cent, lacquer54.6 mg., and appearance rating B. e

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims, or the equivalent ofsuch, be employed.

' We therefore particularly point out and distinctly claim as ourinvention:

1. A process of stabilizing a petroleum out against oxidation,comprising adding diphenylthiocarbazide in an amount sufiicient to actas an inhibitor.

2. A process of stabilizing a petroleum cu against oxidation, comprisingadding phenylthiosemicarbazide in an amount sufiicient to act as aninhibitor.

3. A process of stabilizing a. petroleum out against oxidation,comprising adding o-tolyl thiosemicarbazide in an amount sufiicient toact as an inhibitor.

4. A process of stabilizing a petroleum out against oxidation,comprising adding an agent from the group consisting of thiocarbazidesand thiosemicarbazides containing aryl groups, in an amount sufiicientto act as an inhibitor.

5. A hydrocarbon motor fuel containing a small amount ofdiphenylthiocarbazide sufiicient to act as an oxidation inhibitor.

- 6. A petroleum oil out containing a small amount ofphenylthiosemicarbazide sufficient to act as an oxidation inhibitor.

7. A petroleum oil cut containing a small amount of o-tolylthiosemicarbazide suflicient to act as an oxidation inhibitor.

8. A petroleum cut containing an amount of an agent from the groupconsisting of thiocarbazides and thiosemicarbaz'ides containing arylgroups, in an amount suflicient to act as an oxidation inhibitor.

ROBERT E. BURK. EVERE'I'I' C. HUGHES.

